The present invention relates to a clamp particularly of the type by means of which waveguides are connected, held and fastened to support structures such as transmitter towers or the like.
In order to fasten cable of different diameter to support structure, clamps are used having a lower portion which is fastened to the support structure and an upper portion which is fastened to the lower portion while the cable is held inbetween. The two portions are of complementary contour to receive and hold the cable accordingly.
This type of clamp has been used quite successfully for fastening and holding cable with a yielding insulation jacket. The respective legs of these clamp parts each extending laterally from the contoured portion, are spaced apart by a distance which depends on the diameter of the cable (prior to tightening). For large cable that distance is for example 4 mm. Upon insertion of tightening bolts or the like these legs of the two clamp parts are forced towards each other until abutting while the cable jacket undergoes some deformation on account of the clamping action. This particular deformation is actually part of the interaction between clamp and cable and contributes to the holding and clamping thereof.
It is readily apparent, that waveguides cannot be fastened and held in that manner, because one cannot squeeze them in the stated fashion. The waveguide duct proper does have a jacket, but a deformation is likely to be transmitted to the tube, and squeezing of this waveguide duct would result in a local protrusion which causes reflection of transmitted wave energy. Thus, such a deformation must be prevented, but the waveguide must still be fastened where installed. By way of example, such a waveguide cable must be mounted to the tower of a transmitting antenna or the like. A waveguide is required here to run up for several or many hundred feet, but must be firmly held e.g. against wind etc.
One has to consider also, that the fastening of a waveguide and installing it on such a tower must be a simple procedure which does not require extensive manipulations by the work-man. For example, the probability that nuts, bolts or the like are accidentally dropped from great heights should be avoided because of possible injury to people and other damages.